While metacognitive mastery seems to be closely linked to general functioning in persons with psychosis, little is known of metacognitive capacity of family members, who often play an important role in recovery and often report high levels of distress. We gathered assessments of metacognitive mastery from persons with first-episode psychosis and their mothers. We found that relatively higher overall mean mastery levels among the dyads, was related to less negative caregiver experiences, and less caregiver criticism. Greater levels of mastery were related to decreased duration of untreated psychosis. Clinical implications in terms of family intervention programmes repertoire are discussed.